In our study, the downregulated genes associated with TAO were identified as PLP2, CCL4, CCL4L1, CCL4L2, EGR1, RPL9, LAMP2, PRKACA, TOP2B, DGKZ, ANPEP, TCIRG1, NDUFA1, HBB, and RPL32. The gene discussed is EGR1; the disease is thromboangiitis obliterans.